Cupric gellike absorbent and process of making same



Patented June 2, 1 925.

ROBEBT E. WILSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE BALTIMORE GAS ENGINEERING conroaa'rrou. or BALTIMORE, MARYLAND.

curmc omnrxn ABSORBENT AND pnocnss or mine same;

NoDrawlng. Original application filed January 28, 1920, Serial No. 354,891 Divided tion flled July 9, 1924. Serial No. 725,038.

To all whom it may concern: I

Be it known that I, ROBERT E. WILSON, a citizen of the United States, residing at Chicago, in the county of Cook and State -of Illinois, have invented certain new and" useful Improvements in Cupric Gellike Absorbents and Processes of Making Same;

and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This application is adivision of my copending application Serial No. 354,690

filed Jan. 28, 1920.

This application relates to a dense,. hard, granular, partially hydrated, gel-like absorbent consisting of cupric hydroxide having ultra microscopic pores, and to the process of making the same. Previous to this invention cupric hydro-;ide gel has been made both by dialysis of a colloidal solution of basic cupric chloride for several days using a semi-permeable membrane and following the procedure commonly used in the preparation of true hydroxide gels, as well as by means of direct precipitation of the hydroxide from solutions of copper salts by means of alkalies. While by the former method it was possible to make true cupric hydroxide gels, the process was so extremely slow and expensive that there was no possibility of its being used as a commercial method of making the gel. ()n the other hand, the cupric hydroxides previously made by precipitation, when dried and formed into rough granular material, was found to be soft, resembling soft baked clays and having a very low absorptive power. 'here any specific directions are given for the preparation of precipitated cupric chloride, complete. dehydration is specified. The product of this invention can bemade only when employing the most careful. control of the.- preparation of solutions, precipitation. and drying. It is very hard, dense, and has a vitreous fracture. The best samples hold from 8 to 12 per cent of water after drying several hours in a "acuum at 150 (1.. while ordinary precipitation cupric hydroxide is almost completely dehydrated by this treatment. Cupric l'iydroxide prepared according to the method disclosed in this application is a good absorbent, comand this applicaparing favorably with activated charcoal, with which it may be mixed if desired, against such gases as phosgene and chloroplcrin. It also has a great capacity for the absorption' f water vapor from gases or gaseous mixtures. The material also has advantages wherever a dense, firm structure of cupric oxide, metallic copper, or any copper compounds are desired for catalytic and other purposes.

It was found that certain steps in the production of this absorbent constitute important variables in the preparation of au extremely activeg'el'. The cupric hydroxide is precipitated from a solution of its salts, for instance cupric chloride by means of an alkali such as caustic soda and the precipitate filtered and, dried. The temperature of the precipitate, the pressure in the filter press, and the exact method of dr 'ing are especially important factors. It was also found that a concentration of solutions of from (i to 10 per cent and a reaction tem )erature of from to C. gives the est precipitation. The solution after precipitation should contain an excess of alkali. \Vashiug by docantation should be very thorough. A fairly high pressure should be used in forming the filter cake to squeeze out all excess water. The temperature of dryin is important and should not exceed 225 5, better results being obtained at temperatures below 200 C. The drying should be slow at the start and is preferably performed in two stages, as hereinafter described.

A method of preparation of this absorbent which has been found to give good results is as follows: A 6 per cent solution of cupric chloride in water is poured slowly and with constant stirring into a 6 per cent solution of caustic soda, the amount of cans-- .tic sod-a being somewhat in excess of the moved, ground, and screened to the required mesh and dried for six to eight hours at 150 (3., under a vacuum of twenty-seven or twenty-eight inches. It appears to be of some advantage to boil the sludge for a short time before filtering, filter, and then subject :tbgpreeipitate to high pressure.

though in the specific examples given above certain definite proportions and cific steps are enumerated, it is not inten ed that this-invention be limited to such details of procedure, but it is desired to claim the new gel-like cupric hydroxide and the process of making t e same as set forth in the following claims; for instance, other concentrations of solutions may be used, other alkalies such as ammonium hydroxide ma replace the caustic soda in the precipitation and other salts of copper may re lace the cupric chloride. It is also possib e to produce the new absorbent at reacting temperatures varying somewhat from those specified in the above examples.

What I claim and desire to secure by Letters Patent is I 1. A hard, rough, gel-like material consisting essentially of cupric hydroxide.

2. hard, rough, partially hydrated,

red heat.

geHike material essentially of cupric hydroxide. 3. A partially hydrated gel-like cupric oxide absorbent.

4. A partially hydrated gel-like cupric W oxide absorbent having ultra microscopic pores. I

5. A gel-like cupric hydroxide containing approximately 8 to 15 per cent combined water as determined byigniting to a low 6'. An absoibent comprising gel-like cup 10421 hydroxide mixed with absorbent charsorbents, washing by 'decantation a cupric 7. In a. process of producing gel-like abhydroxide absorbent after precipitation,

and then drying same at about (1., and thhn at about C.

8. In a process oi producing a gel-like absorbent, washing by decantation a cupric hydroxide absorbent after precipitation, kneading and then drying same first at about 110 C. in air, and then about 150 C. in' a vacuum. 7 9. In a. process of producing gel-like'ab sol-bent, washing by decantationa cupric hydroxide absorbent after precipitation,

kneading and then drying same at relatively low temperature, and finally at a relatively higher temperature.

In testimony whereofl a-flix mysignature.

ROBERT, E. WILSON. 

